On Sun, 22 Jun 1997, Glen Ingram wrote:
>
> Actually, I think this interpretation is too fair. These days scientists
> confuse their papers with journalism: their conclusions are sensational
> not original. With the need to attract money for research in biology,
> this trend is increasing. The class-act is someone who has original
> conclusions in their papers but knows how to regurgitate them for
> popular consumption.
And, I may add that this trend is further encouraged by the fact that
it is extremely difficult to get negative results published and need I say
that publications are the researchers bread and better. But enough of
this ....
> Second point, I think there is something in that about animals that can
> teach their young, or each other, passing on information about "good
> manners" when eating toads. This conclusion comes from experience of 25
> years with public inquiries. A recent example, it has only been in the
> last three years that people have been noticing Torresian Crows eating
> toads by breaking through the abdomen and eating the guts. First there
> was, one report, then there were a couple of reports - then an
> avalanche.
>
As you say without proper research it is impossible to say, but there are
data on how and what birds learn that could be useful. For example,
crows and raven are exceptional learners compared to other avian species
probably due to their highly social nature. Hence, observational learning
is to be expected through a crow's life (BTW work with ravens have
indicated that specific individuals seem better able to solve novel
problems and only they learn do others in the flock copy the new
strategy). However, I have never seen any mention in the literature
concerning exceptional learning capabilities of either kites or ducks
other then imprinting. I would guess that the best opportunity to learn
to eat a new food source for ducks and kites (not crows) would occur
during the first months of life -- adults seem to stick to "old" feeding
habits.
> That young can be taught might be more so with birds with precocious
> young. An example, as a kid growing up in Innisfail, north Queensland, I
> use to run around our yard chasing our domestic Muscovy Ducks. They
> would flip toads over, push their bills into the abdomen, then open
> and shut them rapidly, break through the skin and muscle, and then eat
> the toad's innards. (I was chasing them because I thought toads were
> native frogs! It broke my heart when I found out). Yes, it would be good
> to ask someone who might know, "Do they do it in the wild." Or did our
> domestic ducks learn in our backyard and pass it around.
>
Thanks for sharing this. I am wondering whether people who keep chickens
have fewer toads about. How do your ducks open up the toads?
> As well, I have watched swamphens around the University of Queensland
> lake (when there was one only) grab a toad in one foot, lift the
> amphibian towards its bill then ram its bill through the toads mouth,
> eviscerate it, eat the guts and drop the husk. The question is here, "Do
> they feed on native frogs by eviscerating them?" (Once saw a swamphen at
> Bunya Park Zoo - in the kiddy's Old McDonalds Farm area with the cute
> animals - snatch a guinea pig and fly off with it, leaving behind many
> distressed patrons).
I would be surprised if swamphen didn't eat native frogs.
> As to Black Kites, I do not remember them taking toads, or their
> carcasses, when I was young. As said before, one is diurnal and the
> other
> isn't. As well, even though kites are among the first scavengers along
> roads at first light, they have often been beaten to squashed toads by
> giant centipedes, which drag the carcasses off the road. (In Micronesia,
> hermit crabs replace centipedes as the amin road scavengers of dead,
> introduced cane toads).
>
> For Fork-tails, it would be interesting to try and conclude if this is a
> recently accessioned behaviour. It is certainly the first time I have
> heard of it.
Fork-tails? Who mentions this?
Unfortunately, I can't see diurnal birds ever controlling the otad
population. Now, can owls be taught to eat toads or are toads to quiet?
Cheers, Jim
|
